Rotary-driven tools used in machine tools often exhibit concentricity errors or damage, which may be present even before use in the machine tool or can also arise subsequently due to wear of the same.
Concentricity errors or damage to the rotary-driven tool can lead to stresses in the tools that damage or destroy these during machining. In machining processes with small tolerances, concentricity errors of less than 0.01 mm can lead to defective machining and thus to rejects in the production process.
To recognize possible concentricity errors or damage to the rotary-driven tool, one possible approach is to set the rotary-driven tool, clamped in the machine tool, in rotation and measure it using an optical measuring system, for example in the form of a laser light barrier. In this process a signal is generated by shading caused by the rotary-driven tool in a light beam of the laser light barrier, which signal is processed to determine a parameter, for example a radius of the rotary-driven tool, and compare it with a reference radius. A possible concentricity error can be detected based on the comparison.
This approach presupposes that the shading generated by the rotary-driven tool in the light beam was only generated by the rotary-driven tool. This has the disadvantage that, above all when the rotary-driven tool is in use, swarf, cleaning fluid and/or coolant, for example, can have an influence on the shading of the light beam that is generated, so that the resulting signal reproduces an incorrect radius, for example. The vibrations produced by the operation of the machine tool, which can lead to a distorted signal, are another influencing factor. The consequence of the possibly excessive deviation from the reference radius would be that the rotary-driven tool would be exchanged or stopped, leading in turn to a stoppage of the machine tool. The consequences of the stoppage of the machine tool are lower production efficiency.